Robust Broadband Maritime Communications: Theoretical and Experimental Validation

• Published in: Radio science 2018-06, Vol.53 (6), p.749-760
• Main Authors: Couillard, Denis, Dahman, Ghassan, GrandMaison, Marie‐Eve, Poitau, Gwenael, Gagnon, Francois
• Format: Article
• Language: English
• Subjects: Band theory; Broadband; C band; Computer simulation; Ducts; Fluctuations; Frequencies; Links; Lower atmosphere; Mathematical models; Refractivity; Sunrise; Sunset; Theoretical analysis
• ISSN: 0048-6604; 1944-799X
• DOI: 10.1029/2018RS006561

Atmospheric ducts, which are caused by the rapid decrease in the refractive index of the lower atmosphere, have been recognized as the dominant propagation mechanism for long range maritime links. Recent advances in radio technology are making reliable high‐capacity overwater links a reality. A ray‐tracing simulation model was developed to obtain reliable prediction of maritime link performance beyond 30 km for realistic conditions. A series of static and mobile long range maritime multiple‐input multiple‐output links were tested with representative antenna heights at 1.39 (Band 3 or L‐Band) and 4.5 GHz (Band 4 or C‐Band) during periods with various levels of ducting activities, for example, sunset and sunrise times. Measured link performance and observed ducting occurrences are compared to predictions to validate the model ability to accurately predict and explain link performance for various ducting conditions. The test results agree with the model predictions and illustrate the various Received Signal Level degradation, enhancement, and fluctuations that can be expected in long range maritime links below 6 GHz. We also report on short‐term (few to several minutes) fluctuations of the received signal level at the two measurement frequency bands during high ducting activity periods. Measurements and theoretical analysis of the effect of ducting on the quality of maritime communication links indicate that both reflection‐induced and ducting‐induced disruptions are different and more frequent in higher‐frequency bands. This work opens interesting perspectives on providing more robust and more predictable communications in the presence of ducting. Key Points Shore‐to‐shore and ship‐to‐shore overwater propagation measurements in the L‐Band and C‐Band are performed Ray‐tracing simulations are used to predict and study the behavior of the measured channel Received signal level fluctuation due to various ducting conditions is reported and explained